This study examines the effects of using mobile phones to promote the HIV prevention knowledge among the village doctors in Beihai, Guangxi, China. Data was derived from the baseline survey of an mHealth-based HIV prevention and care training project among village doctors. Of the 228 participants who completed the questionnaires, 80.3% were male, 32% received a college or higher education, and 74.4% had a monthly income below 3,000 RMB (≈434 USD). Their average HIV prevention knowledge score was 5.56 ±1.84. The participants' HIV prevention knowledge was found to be positively associated with the frequency of accessing the Internet using mobile phones, online information searching, and accessing social media using mobile phones. The results indicated that future library services should consider mobile phones as an effective tool for disseminating HIV prevention knowledge via online approaches. [ABSTRACT FROM AUTHOR]